Error: The XML declaration must be the first node in the document

Question

I am getting \"Unexpected XML declaration. The XML declaration must be the first node in the document, and no white space characters are allowed to appear before it\" error

Answer 1

As the error states, the first five characters of an XML document should be . No ifs, ands or buts. The comments you have above the opening XML tag are illegal; they must go inside the XML tag (because the comment structure is itself defined by the XML standard and so is meaningless outside the main XML tags).

EDIT: Something like this should be able to rearrange the rows, given the file format from the OP:

var lines = new List();

using (var fileStream = File.Open(xmlFilePath, FileMode.Open, FileAccess.Read))
   using(var reader = new TextReader(fileStream))
   {
      string line;
      while((line = reader.ReadLine()) != null)
         lines.Add(line);
   }   

var i = lines.FindIndex(s=>s.StartsWith("